The IGEL H860C has a InsydeH20 BIOS. From the dmesg
output I see:
efi: EFI v2.70 by INSYDE Corp. .... DMI: IGEL Technology GmbH H860C/H860C, BIOS H860C V:3.2.13A-12182020 12/18/2020
Hit the DEL key to interrupt the normal boot sequence.
This takes you into the BIOS via an intermediate screen labelled Front Page. This presents you with 5 options:
Continue
►Boot Manager
►Device Management
►Boot From File
►Setup Utility
These are self evident.
In the Setup Utility there are a limited number of options under the usual pages of
This is a UEFI BIOS. There is no option for legacy booting.